This invention relates generally to the assembly of printed circuit (PC) boards and is particularly directed to the crimping of leads or tabs of electronic components inserted through apertures in a PC board.
PC boards may include many different kinds of components, such as resistors, transistors, capacitors, potentiometers, coils and others. During fabrication, the PC board is formed with apertures which are adapted to receive the leads and tabs of various of the aforementioned components. With the leads of these components inserted through the aforementioned apertures in the PC board, electrical contact is established between these leads and various conductors on the PC board by bending these leads so that they are in intimate contact with one or more conductors. The bending of these electronic component leads is termed "crimping." Component tabs are similarly inserted through PC board apertures for the purpose of mounting the component to the PC board. In the following discussion and description and for purposes of the present invention, the terms electronic component leads and tabs are used interchangeably and are considered to be equivalent structures.
The fabrication and assembly of PC boards is increasingly being accomplished using high speed, automatic machines and methods. This approach generally makes use of robotic machines which insert the various electronic components on the PC board and then crimp the electronic component leads in electrical contact with various electrical conductors on the PC board. Each of the PC boards is positioned in sequence with respect to these robotic machines by means of a high speed conveyor system which facilitates the rapid assembly of the PC boards.
Prior art approaches in the high speed, automatic crimping of electronic component leads inserted through a PC board have suffered from being overly complex resulting in high costs and low reliability of these installations. For example, where a large number of crimping elements are used to crimp a corresponding large number of electronic component leads, each crimping element has associated therewith a respective actuating mechanism. This not only increases the number of crimping components involved, but also requires that precise alignment between each actuating mechanism and its associated crimping element be maintained. Furthermore, a large space is generally required to accommodate the large number of actuating mechanisms making this approach difficult to integrate into a PC board conveyor system where component insertion and lead crimping is accomplished by operator controlled apparatus. These large, bulky installations make operator positioning adjacent to the conveyor system difficult and inhibit direct viewing of the PC boards and electronic components installed thereon which the operator must have to exert proper control over the assembly process.
Because of the large variety of PC boards and combinations of electronic components positioned thereon, a PC board conveyor system must be capable of accommodating the assembly of various PC boards. To accommodate the various configurations of different PC boards as well as the arrangement of electronic components thereron, those components of the PC board assembly system involved with crimping of component leads must be matched to the configuration of the PC boards being assembled. The prior art has required not only the replacement of the individual lead crimping elements, but also each of their associated actuating mechanisms when the conveyor system is modified to accommodate another PC board configuration. This not only increases the complexity and cost of the PC board assembly system as well as the time to change over from one PC board configuration to another, but also reduces its adaptability to accommodate a wide range of PC board configurations. In addition, current lead crimping arrangements in PC board assembly conveyor systems incorporate various structures on the crimping assembly which limit the locations on the PC board at which electronic component leads can be crimped. The arrangement and configuration of the electronic components installed on the PC board is thus restricted to those component positioning and spacing arrangments which can be accommodated by the crimping mechanism taking into consideration the structures disposed thereon.
The present invention is intended to overcome the aforementioned limitations of the prior art by providing an improved electronic component lead crimping apparatus which employs a common actuator means for actuating each of a plurality of crimping elements which may be arranged in virtually any spaced array to accommodate virtually any positioning arrangement of electronic components on the PC board. The lead crimping apparatus of the present invention is comprised of a relatively small number of components and occupies a small space, and is easily positioned immediately beneath a PC board conveyor system while still allowing for the legs of a conveyor system operator to also be positioned beneath the conveyor. Electronic component leads are engaged by the individual crimping elements as the crimping element is displaced generally parallel to the plane of the PC board in an arrangement which does not require precise alignment between the component lead and the crimping element. The lead crimping apparatus is capable of accommodating virtually any arrangement of electronic components on a PC board and is adapted for ease of interchangeability of those components which must be matched to the electronic component array on the PC board.